(1) Field of the Invention
This invention relates to light source of a projector, in particular to the use of light emitting diode matrix as light source. This patent application is co-pending with U.S. patent application Ser. No. 09/982,371, filed Oct. 19, 2001; now U.S. Pat. No. 6,650,048.
(2) Brief Description of Related Art
FIG. 1 shows a prior-art three-gun projector unit 100 for color display. A projector lamp 10 projects a full color light beam L to a prism 11, which splits the light into a blue light beam B, green light beam G and red light beam R. The split light beams B, G, R pass through three transmissive liquid crystal display plates 12B, 12G, 12R, respectively, which control the timing and the amount of transmission through each plate. The transmitted light beams transmit past three corresponding lens 15B, 15G, 15R and project onto a screen 18 to display a full color picture. By changing the transmission through each liquid crystal plate rapidly with time, the display on the screen presents a motion picture like that in a television or movie.
FIG. 2 shows the structure of a traditional lamp 10 for the projector shown in FIG. 1. The filament 102 is located near the socket 101 of the lamp with a lamp shade 103. From the standpoint the energy efficiency, environmental protection and desirability for higher light intensity, the traditional filament-type projection lamp suffers from high energy consumption and overheating.